1. Field of the Invention
The present invention relates to a printer in which an ink ribbon and paper on the ink ribbon are carried between a print head and a platen, in a state such that they are pressed against each other, for printing on the paper.
2. Description of the Related Art
Hitherto, the above kind of a printer has been provided with a ribbon installing unit. The ribbon installing unit has a configuration in which the unit is provided with a ribbon supply shaft and a ribbon winding shaft, and the ink ribbon installed on the ribbon supply shaft is wound onto the ribbon winding shaft after passing between a printing head and a platen.
It is preferable that predetermined winding tension is applied to the ink ribbon which is wound onto the ribbon winding shaft, and, when there are variations in the above winding tension, there is a possibility that wrinkles are generated on the ink ribbon during printing to cause printing problems.
A conventional printer in which the torque of the ribbon winding shaft is adjusted in order to apply predetermined tension to the ink ribbon from the start to the end of ink ribbon winding has been known.
Though there have been conventional printers in which a plurality of kinds of ink ribbons, which are different in the size from each other, can be installed, there have been no printers in which the torque of the ribbon winding shaft may be adjusted to the best one according to various kinds of ink ribbons which are different in the size from each other. For example, even when there are different kinds of ink ribbons, for example, ink ribbons with a narrow width and those with a broad width, the torque of the winding shaft has been adjusted to the same values for the above different ink ribbons. Accordingly, when the axial torque is set to a suitable value, for example, for a ink ribbon with a broad width, excessive tension is applied to a ink ribbon with a narrow width. That is, there has been a possibility that wrinkles are generated on the ink ribbon and printing problems are generated.